Drafting instrument



March 24, 1942. E. w. CARLTON DRAFTING INSTRUMENT Filed March 20, 1941 Edward 6'ar/f0/0,

Patented Mar. 24, 1942 UNITED STATES PATENT OFFICE DRAFTING INSTRUMENT Edward William Carlton, Chicago, 111. Application March 20, 1941, Serial No. 384,411

3 Claims.

My invention relates to drafting instruments and more particularly to drafting pens operable for forming lines of various widths.

One of the principal objects of my invention is to provide a pen of the above described character equipped with micrometer means whereby the width of the lines to be drawn by the pen may be conveniently and accurately regulated.

An important object of my invention is to provide a device of the character described which is simple in construction, durable in use, efficient in operation and economical in manufacture.

With the above and other objects in view, as will hereinafter appear, the invention consists in the combination, and arrangement of parts hereinafter set forth and illustrated in the accompanying drawing, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

Referring to the drawing wherein like reference characters designate like parts throughout the several views:

Figure 1 is a side elevation of a ruling pen equipped with my invention.

Figure 2 is a view similar to Figure 1 with certain of the parts being in section.

In the embodiment of my invention illustrated in the drawing, I employ a ruling pen provided with a pen section 6 formed with a pair of relatively movable front and rear blades I and 8 respectively. The blades terminate at their lower ends in nibs 9 for ruling or forming lines by means of ink contained between the blades and fed downwardly between the nibs. The upper ends of the blades are structurally integrally connected together and are of a sufficient resiliency whereby one blade is normally urged in a direction away from the other. The outer blade I is formed with an opening II] through which extends a screw II, the head l2 being rotatably seated within a countersink I3 formed in the front face of the blade I.

The rear face of the blade 8 is formed with a boss l4 having its peripheral face provided with a scale marking I5 for a purpose hereinafter made apparent. The blade 8 is formed with a threaded bore I6 which extends through the boss and has adjustably mounted therein a threaded pin or member I I. The front end of the pin I! has threaded therein the shank I8 of the screw I I whereby to maintain said pin in connected relation with the blade I and preclude axial movement relative thereto. The opening l0 and the countersink l3 are of a materially greater diameter than the diameters of the shank and head respectively of the screw whereby to permit rotation of the pin and screw with respect to the blade I and to permit abaxial displacement of the pin when the blade I is adjusted relative to the blade 8 as hereinafter set forth.

The blade 8 is formed with a transverse slot I9 in which is rotatably mounted a cylindriform lock nut 20, the latter being threaded on the member I? and coacting with a wall defining the slot I9 to lock the member I! in an adjusted position thus maintaining the blades relatively fixed.

The rear end of the pin I! is provided with a cap 2I formed with a skirt 22 disposed about the boss I4. The front face 23 of the skirt 22 is beveled and provided with calibrations 24 for selective registry with the marking I5 for denoting the position of the nibs 9 with respect to each other, thus enabling the operator to accurately gauge the width of the line to be drawn by the pen.

The lock nut 20 is of a greater diameter than the width'of the blade 8 whereby lateral portions of the lock nut extend an appreciable distance beyond the blade 8 to facilitate operation of the nut. Both the lock nut and the skirt have their outer circumferential faces knurled to provide an easy finger grip for the operator when adjusting the blades.

It will be apparent that by loosening the lock nut 20, the member I! may be rotated in a desired direction to effect adjustment of the nibs in accordance with one of the calibrations 24. When the member II and the nibs have thus been adjusted, the lock nut 20 is operated to clamp the member II against further adjustment of the blade I whereby a line of a desired width may be drawn by the pen.

It is to be understood that the calibrations 24 comprise a plurality of spaced lines arranged about the skirt in a manner to accurately denote the distance between the nibs when brought into selective registry with the marking I5. If desired, suitable indicia may be provided on the skirt, for instance, numerals to identify the markings respectively. While I have disclosed my invention as being applied to a ruling pen, it is to be understood that the same may be applied to other similar instruments, for instance, bow and compass pens.

Without further elaboration the foregoing will so fully explain the invention that others may, by applying current knowledge, readily adapt the same for use under various conditions of service.

Moreover, it is not indispensable that all the features of the invention be used conjointly since they may be employed advantageously in various combinations and sub-combinations.

It is obvious that the invention is not confined to the herein described use therefor as it may be utilized for any purpose to which it is adaptable. It is therefore to be understood that the invention is not limited to the specific construction as illustrated and. described as the same is only illustrative of the principles of operation, which are capable of extended application in various forms, and that the invention comprehends all construction within the scope of the claims.

What I claim is:

1. A drafting pen equipped with a pair of relatively adjustable blades having nibs for forming lines of various widths, one of said blades provided with a cylindriform boss having a scale marking on its periphery, a threaded pin swivelly connected to the other blade and threaded through said first defined blade and boss and movable for effecting relative adjustment of said blades, said first defined blade formed with a slot through which said pin extends, a lock nut threaded on said pin and disposed in said slot and coacting with one of the walls defining said slot to lock said pin against movement, a cap carried by said pin and formed with a skirt surrounding said boss, said skirt provided with calibrations for selective registry with said marking for denoting the relative positions of the nibs of said blade.

2. In combination, a drafting pen equipped with a pair of relatively adjustable blades for forming lines of various widths, a member swiveled to one of said blades and threaded through the other for eifecting relative adjustment of said blades, one of said blades formed with a slot through which said member extends, and a lock nut threaded on said member and disposed in said slot and coacting with said member and said last mentioned blade to lock said blades against adjustment.

3. In a drafting pen including a pair of relatively adjustable blades for forming lines of various widths, a member swiveled to one of said blades and threaded through the other blade for efiecting relative adjustment of said blades, one of said blades having a slot through which said member extends, and a lock nut located partly within the slot and threaded on said member and engageable with a wall of the slot to secure said member against rotation and thereby maintain said blades in various adjusted positions.

EDWARD WILLIAM CARLTON. 

